Method and apparatus for ore concentration.



UNITED STATES PATENT GFFIGE.

EDWARD HOIT NUTTEB, OF NEW YORK,

LONDON, ENGLAND, ASSIGNORS TO M DON, EN GLAND.

METHOD AND urana'ros Application filed September To all whom itmag concern:

Be it known that we, Enwxnn Herr NUT- rm and THEODORE J Essa Hoovan, citizens ofthe United States of America, residing, re

spectively, in the cit of New York, county and State of New ork United States of America, and London, England, have invented certain new and useful Improvements in Methods and A paratus for Ore Concentration, of which t e following is a specification.

This invention is for improvements in or relating to a method and apparatus for ore concentration.

Several processes are known in which certain articles are raised to the surface of a liqui containin powdered ore in suspension, by means 0 bubbles of air or gas that have been caused to attach themselves to these certain particles which are. thereby caused to float while other articles are not so floated. Thus the pow ered ore mixed with water containing a mineral-frothing agent may be agitated so as to beat air into the liquid and iform a coherent froth by which certain constituents of the oresuc as metallic sulfids are floated.

One object of this invention is to improve the apparatus used in this type of process,- and a aratus constructed in accordance with t is invention is a plicable for use in any of the well known roth flotation processes of ore concentration.

In a pJarat'us at present in use in which a mineral earing froth is formed and collected it is customary for the froth to be removed from the main pul after the froth has reached a free air sur ace so that if the gaseous bubbles or some of them burst on reaching the free air surface there is a possibility that some of the mineral contents of the froth will fall back into thepulp or circuit liquor and fail to be separated and this does in fact occur with tender froths from which the mineral has a tendency to shower.

According to this invention a method of ore concentration by the formation of a mineral bearing froth consists in causing the froth as it is formed to fall over a trap, battle or wall below the level of the free on surface whereby thefroth is collected and removed from the pulp before the bubbles can. burst.

Specification of Letters Patent.

N. Y., AND THEODORE JESSE HOOVER, OF INEBALS SEPARATION LIMITED, OF LON- FOR ORE CONCENTRATION.

Patented Apr. 14, ram.

25, 1911. Serial No. 651,188.

An up aratus for concentratin ores by aseous otation of certain minera particles in liquid according to this invention comprises the combination with an agitating vessel in which the liquid containing a min- 'eral frothing agent and containing powdered ore in suspension is agitated so s to beat air into it, of a conduit through w ich the frothpasses and a tra .to catch the froth before or as the bubb es reach a free air surface whereby the froth is collected and removed from the pulp. Thus the conduit throu h which the froth is caused to pass may lave a wall, partition or lip the top of which is below the normal surface of the froth or at an rate below the free air surface of the frot whereby the froth falls over the wall or lip and is trapped before the bubbles in the froth can burst so that the mineral contents of the bubbles which burst are discharged into the trap compartment and not into the pulp. It is pomible to arrange that the froth passes directly out of the mixing vessel and over a lip or trap which is below a free air surface and over which the froth passes whereby the froth is collected immediately after it is formed and removed from the pulp before the bubbles can reach the free air surface and burst.

A feature of this invention consists in the combination with two or more mixing vessels of a passage or separate compartment through which the ore )ulp travels in assing from one vessel to the other and a roth conduit from said passage or compartment so that the froth is led away and trapped while the pulp is passin from one vessel to another. A practical form of this apparatus comprises a number'of mixing and separating vessels substantially on the same level. Passages outside the vessels or separate intermediate compartments connect each vessel with the ad acent vessel and a -froth conduit and trap are arranged at each passage or intermediate compartment where- )y the froth formed at each stage of the agitation is led away and trapped while the pulp passes through the series of mixing vessels, passages or compartments. .The mixin vessels may be connected together in pairs y orifices in the partitions between them, and the paaiabges outside the vessels ma3r,:be arranged connect one vessel of each pair with the ad'accnt vessel of the next pair, a froth trap eing placed at each passage. .f

In any of the arrangements described above this invention includes the combinetionwith a first lip which is below the free air surface and over which the whole froth passes into a trap of a second lip over which the more permanent froth passes from the trap into a launder or other collector, and various arrangements may be used for removing the concentrates that sink to the bottom of the trap compartment.

In the accompanying drawings which illustrate by way of example one form of apparatus embodying this invention, Figure 1 is a front elevation partly in section; Fig. 2 is a transverse section, and Fig. 8 is a plan of the apparatus.

Several mixing vessels A are laced side by side on the samelevel. Eac vessel is provided with a rotatable agitator or stirrer A carried by a vertical spindle A rotated at hi h speed by any convenient means. The first vessel is connected with the second, the second to the third, the third-to the. fourth and so on by passages or compa rtments 13 between the mixing vessels and on the same level with them. By this arrangement the pulp passes from the first vessel A through the connecting passage or compartment so on and at the end of the series the pulp may conveniently be passed into a spitzkastcn as described in the previous patent to Hoover, No. 953,746, of April 5, 19l0.-

At each connecting passage or compartinent B there is a froth trap, that is to say baffles or conduits are so arranged in connection with these passages that the mineral-bearing bubbles in'rising are directed into a so )arnte compartment from that throu h which the main circuit passes, before tie bubbles reach the-free air surface and have a chance to break. Thus, for example, the wall of each connectin passage 13 may be formed by a artition the top or lip D of which 1s be ow the level of the free air surface of the froth when the apparatus is working.

The froth rises in the connecting passage B and a roof or cover E is provided to lead the froth over the lip or partition D before the bubbles get to a free air surface. Outside the lip or partition is a trap compartment 1 into which the mineral-bearing froth falls or passes. The froth reaches a free air surface in this trap compartment F and the bubbles which-burst deposit the mineral in the trap compartment; The outer wall G of the trap compartment may comprise a second lip G higher than the first; and the more permanent froth will collect in the tra compartment F and flow over the second lip' G into a launder H and to the second vessel A andopportunity of separating. o

in most cases it will be found that the froth passing into the launder will carry the cleanest concentrate.

Any suitable means may be employed for removing the mineral from the trap compartment. If the mineral is not a clean concentrate or if it contains mixed minerals it may be re-treated conveniently in an apparatus similar to the one'just described.

It will be seen that the apparatus can be made in an extremely compact form as the pulp remains substantially on the same level throughout.

The apparatus affords a solution of many problems. There are many ores which are poor in sulfids, or which do not readily roth or which form a froth which is ten-' der. The tendency in such cases is for the bubbles to break as the froth reaches the surface of the pulp and for part of the mineral to sinkback into the pulp. With some frothing agents it is quite possible to get the mineral to the surface'but a permanent froth is not usually formed but by the use of the apparatus embodying this invention substantially all the mineral which is floated is collected. lVith the frothing apparatus at present in use the froth does not have an opportunity of separating until.

the pulp as a whole has undergone a certain period of agitation. With some frothing agents the normal agitatiomis too long that is to say mineral-bearing froth formed during the commencement of the agitation is destroyed again'before the froth has an With the present ap aratus however t froth will come off ant be-trapped immediately after it is formed.

Another important problem was to provide a plant which will lend itself to the separation of the different metalliferous rpnstituents of an ore by differential flotahon. Lavers, No. 1,064,723, of June 17, 1913, is described a process of obtaining successive mineral bearing froths and by conducting the mixing operation under varying conditions and thereafter treating the different froths again under differentiating conditious. The apparatus embtxlying this invention affords ready means for carrying out such .a process as the froth may be trapped. re-treated and trapped again exactly at the stages required fordifferentiating between the different flotablc constitucuts.

The details of the apparatus may be varied without departing from this invention, thus the form of the conduit through which the froth passes away from the pulp may be widely varied as such conduit may be formed by suitably directed baffles, walls, tubes and the like.

The method of conveying the mineral In the patent, to Greenwuy andconsists in mixing the ore wit from the trap compartment may be by spitzluten, by continuous water flow, b positive conveyer, by automatic valve or 'ot erwise.

What we claim as our invention and desire to secure by Letters Patent is 1. A method of concentrating ores by the formation of a mineral-bearing froth which consists in causin the froth as it is formed to pass over a lip elow the level of the free air surface, causing the body of the pulp to pass onward to further treatment without passing over said lip and causing the more permanent froth of the froth thus separated to pass over a second lip.

2. A method of concentrating ores by the formation of a mineral bearin froth which consists in agitatin an ore pu p mixture to aerate the same, eading off the agitated and aerated mixture and entrapping the froth as it is formed and separatin the froth from the mixture before the bu bles can reach a free air surface and burst, and further separating the more permanent froth from the froth which was entrapped as it was formed.

3. A method of eoncentratin ores which water containing a mineral-frothing a at, a 't ating the mixture so as to beat air into it eading off the agitated and aerated mixture in which a froth forms, deflecting or aiding the froth as it rises, entrapping the roth as it forms and separatin tie froth from the liquid before the bubb es can reach a free air surface and burst, and further separatm the more permanent froth from t e froti which was entrapped as it was formed.

4. In an a paratus for concentratin ores by gaseous otation of certain minera par ticles in li uid, the combination of a vessel havin agitation froth forming .means, a conduit leading from the froth formin vessel to convey the liquid and the frot which forms therein, a trap to catch the froth before the bubbles reach the surface, and an overflow lip for the more (permanent froth of the froth thus entrappe 5. In an a iparatus for concentratin ores by gaseous otation of certain minera parholes in liquid the combination of a vessel having agitation froth forming means, means formin an outlet passage leading therefrom, an a lip in the wall of said passage which is below the free air surface and over which the froth passes, whereby the froth iscollected and removed before the bubbles can burst.

-' G. In an a paratus for concentratin ores by gaseous otation of certain minera parholes in liquid, the combination of a vessel having agitation froth forming means, means forming an outlet passage leading therefrom, such passage-forming means havof sai ing a wall the top of which is below the free air surface and over which the froth passes, a trap com artment to receive said froth, and means or separating the more permanent froth in said trap compartment.

7. In an a paratus for concentratin ores by gaseous otation of certain minera partlcles in liquid, the combination of a plurality of vessels having a itation froth forming means and arrange substantially on the same level, means or ways outside the vessels connecting each vessel with the next adjacent vessel, and a froth trap at each passageway, whereby the froth formed at each Sta 6 of the a 'tation is led awa and trapped efore the ubb s reach a co air surface while the pa p passes through the series of froth-forming vessels.

8. In an a paratus for concentratin ores b gaseous otation of certain minera particles in liquid, the combination of a vessel having agitation froth formin means, means forming an outlet passa e t erefrom, a partition in the passa e an a roof over the passage to lead the roth formed in the passage over the lip or partition before the ubbles get to a free air surface.

9.. In an a paratus for ooncentratin ores by gaseous otation of certain minera partlcles inliquid, the combination of a vessel having agitation froth forming means, means forming an outlet passageway therefrom, a artitlon in said passageway having a lip be ow the free air surface in said passa e, a roof to lead the froth over the lip be ore the bubbles et to a free air surface, a second lip over which the more permanent froth (passes, and a launder on the other side second lip.

10. In an apparatus for concentratin ores by gaseous flotation of certain minera parholes in liquid, the combination of a plurality of vessels having agitation froth forming means, means forming connecting passatges between said froth formingvessels, and roth traps in said connecting passages arranged to trap the bubbles before they reach a free air surface.

In testimony whereof we have signedour names to this s ecification in the presence of two subscri ing witnesses.

EDWARD HOIT NUTTER. THEODORE JESSE HOOVER.

Two witnesses to the signature of Edward Hoit Nutter:

C. L. M. NOBLE, M. I. Lawmmos. Two witnesses to the signature of Theodore Jesse Hoover:

O. J. WORTH, R. C. TiuanwnLL.

copies at this patent may be obtained for he cents each, by Miranda: the fflommlaalaaer of Patents, Washington, D. 0."

ming passage- 

